Quick Failover Algorithm in SCTP draft-ietf-tsvwg-sctp-failover Y. Nishida, P. Natarajan, A. Caro, P. Amer, K. Nielsen IETF92, Dallas

Status -08 for WGLC – Technical comments received from Martin Becke and Rob Braden. – Post WGLC review (on ) performed By Gorry Fairhurst 09 not adequate to address all WGLC comments [PFMR=0 does not disable] Further issues on standard language + request for additional elaboration on the motivation for certain standard language requirements RFC4960 Update flag Issue -10 submitted to address the above Differences -08 to -10: – Clarifications. No “intended” change of function, “except” still changes of standard language. Michael Tuexen review on version 10: – Issue for security section, remove cc text description, HB transmittal in PF state, dormant state Self-comment on Standards Language om api events in -10

Version -08 to -10 Clarifications WGLC: Why does PFMR=0 not mean SCTP-PF logic off. New text clarifies: – PFMR does not control activation of SCTP-PF logic – PFMR controls PF state threshold for reach of PF state – PFMR >= PMR means no PF state for destination address HB transmittal during PF state: – HB MUST be sent per RTO in PF state – Text un-clarity on whether RTO back-off is done or not (yes) addressed by using RFC4960 formulations (no keywords) Michael Tuexen comment on -10: For consistency HBs in PF state should honor user configuration. Proposed resolution: – HBs in PF state MUST honor user configuration for RFC4960 HB – HBs SHOULD be sent per RTO in PF state

Michael Tuexen Comments Document Security Issue of PF – PFMR=0 makes is easier for an attacker to make SCTP MH change path – Even more forceful with Permanent Failover – To adopt in next version Enforce Dormant state as non-SCTP PF specific feature: – SCTP continues to transmit in dormant state – SHOULD for SCTP-PF because SCTP-PF should not compromise disruption tolerance compared to RFC4960 – Feature also beneficial for RFC4960 SCTP tolerance -> propose as feature in its own right. – To adopt in next version Remove congestion control language (even if no change intended of RFC4960 ) - to adopt in next version

Standards language on API -10 says: 10. The SCTP stack SHOULD provide the ULP with the means to expose the PF state of its destinations as well as the means to notify the state transitions from Active to PF, and vice-versa. When doing this, such an SCTP stack MUST provide the ULP with the means to suppress exposure of PF state and associated state transitions as well. 10. The SCTP stack should provide the ULP with the means to expose the PF state of its destinations as well as the means to notify the state transitions from Active to PF, and vice-versa. When doing this, such an SCTP stack is recommended to provide the ULP with the means to suppress exposure of PF state and associated state transitions as well. To be changed to (no standards language on API)

RFC4960 Update flag ? This PS complements, but does not update, RFC4960 No comments have been received to the contrary – but question raised by wg chairs. Can we consider this issue as being resolved ?

Proposed Next Steps All technical issues raised, including standards language, are (believed to have been) resolved. BUT… some re-structuring would still be beneficial given PS Next step would be a -11 revision: – Implement the agreed technical resolutions – Still improve language and some restructuring Wg chairs to decide if second WGLC is required Hopefully then ready for the IESG (before IETF93?)